Food residue is often found coating the inside of microwave ovens, especially industrial, commercial and educational settings. Over time, the accumulation of the food produces an unsightly mess that is also difficult to clean, as the material is repeatedly dehydrated to aggressively adhere to the surface. Attempts to scrub away the particulate by conventional method (i.e. abrasive sponge with soap and water) are time-consuming and may damage the plastic walls of the microwave. The process is also difficult because the worse part of the mess is often on the top of the oven, the area that is the hardest to see and clean. While microwave ovens have become symbolic of being quick and easy to use, the same is not true of cleaning them.
This problem has been noticed and several patents have been issued applying alternative solutions.
Several patents have been issued to address this problem. U.S. Pat. Nos. 4,481,395 and 5,290,985 keep the walls of the microwave oven clean by placing inserts into the oven, relying on conventional cleaning methods (washing, scrubbing, drying) to be used when the insert is removed. A dishwasher may be used, if one is around. Also, these devices consume some of the usable volume inside the oven.
In U.S. Pat. Nos. 4,633,052 and 4,778,968, non-flammable, pre-sized paper is used to cover the floor of microwave oven. Once the paper becomes soiled, it is thrown out and replaced with a new sheet. Though these patents protect the floor, the walls and ceiling are overlooked. The ceiling generally accumulates the majority of the food debris while being the more difficult area to clean.
Furthermore, each of the above-mentioned patents necessitate the device to be custom-dimensioned (in as many as three axes) for use in each different size of microwave oven. This represents a significant limitation.
Other inventions have realized this problem of soiling a microwave oven and have attempted preventive solutions. These inventions, such as U.S. Pat. Nos. 4,721,140 and 5,436,434, use splatter guards to minimize the expulsion of food material onto the inner surfaces of the oven.
U.S. Pat. Nos. 4,560,850, 5,313,878, 5,432,324 and 5,558,798 have been issued for releasing steam or moisture for the use of cooking or steaming food. Also, U.S. Pat. Nos. 3,753,651 and 4,861,956 address the sterilization of surfaces, of items brought into the oven, by the use of microwave radiation and/or steam. All of the above mentioned patents ignore cleaning the interior of the microwave oven.
It is therefore desirable to have a simple, quick, low-cost means of cleaning a microwave oven that saves effort to clean the oven while not disturbing normal microwave activities. Moreover, the power of the oven should be utilized to clean itself. The device should not require customization or resizing to work in different sizes of microwave ovens. All materials should be non-toxic, so any residues would not pose a threat to health.
The instant invention is a cleaning device consisting (in its simplest form) of an open cell container used to hold a non-toxic, aqueous solution that may contain surfactant(s) such as TERGITOL(trademark) 15-S-9, d-limonene and/or an emulsifier such as ethoxylated-soybean oil. Details are provided below. The method of use is to place the device into the microwave oven that is then turned on for approximately five minutes, followed by a period of an additional five minutes while the oven door remains closed, allowing the solution to penetrate the caked-on material. The door is then opened. Food residues, which previously held aggressively to the interior of the oven, may be thoroughly wiped clean with a soft sponge or towel. Many residues fall off. The invention works impressively well.
There are four factors to the efficaciousness of the invention: 1) the vapor phase of the solution, created by heating with microwave energy, has a direct effect of softening the residue by steaming; 2) the surfactant is borne by the vapor phase of the solution to the residue at any location in the oven, where it bonds to any remaining oils; 3) the xe2x80x9ccool-downxe2x80x9d period allows the solution to leave the vapor phase, condense and penetrate more deeply into the residue, also carrying surfactant deeper inside; 4) the wiping down phase, in which the heated solution remaining in the device is used to wipe down the surfaces of the oven. During the vapor phase, any fragrance or scent is distributed throughout the room in which the oven resides. The result is a highly efficacious, low cost, non-toxic, microwave oven cleaning method. The volume of solution used for a cleaning must be sufficiently small so that it will boil for a predominance of the on-time of the oven (during cleaning), in the range of 80-100 mL. The volume of the solution must be in accord to the cooking time and concentration of surfactant. Though some of the surfactant will be borne onto the interior surfaces of the oven, much will remain dissolved in the solution of the reservoir. The surfactant will slow the loss of water in the reservoir; therefore, maintaining a protective material for excess microwave energy.
In the solution, the proposed surfactants are non-toxic, making the invention completely safe in the event any residues are left after the cleaning process. Scent such as lemon or pine may be added to produce a pleasant smell. Antibacterial compound may be added without degrading the effectiveness of the process.
Several embodiments are disclosed for an open-cell container including: a simple dispenser with a tear-off membrane seal; a sponge that is soaked with solution; an integrated dispenser and sponge with a tear-off cover; an integrated dispenser and sponge in which the solution is released by penetrating the sponge; a dispenser with a fill line and sponge; and a dispenser with an attached bottle hanger and sponge.